Exploding Tank in Utila

[tridacna]

tridacna again you are dead wrong about the stickers ( here in Ontario if you have a vip sticker from a NON_VERIFIABLE shop or agency MOST shops will tell you to go somewhere else (dive shop owners KNOW people do exactly what you are telling them to do ), if some one is SO cheap they cant or wont have the tank looked at and maybe save a life welllll...........im the only air fill in 100 miles ill fill a 6351 if its had a vaild eddy ...again if I trust the person /company who did it , REMEMBER ITS MY LIFE IM RISKING FOR 10 BUCKS !!! go to tobermory and spot the crap you just did and try to fill your tanks see what happens , those guys WONT fill anything over 10 years old .........

Nice meaningless rant. Yelling in CAPS is a nice touch to make you sound very angry about this really “serious” problem. Do you do this because you seriously think that people print their own stickers? What a bunch of baloney.

 

[Sam Miller III]

tridacna again you are dead wrong about the stickers ( here in Ontario if you have a vip sticker from a NON_VERIFIABLE shop or agency MOST shops will tell you to go somewhere else (dive shop owners KNOW people do exactly what you are telling them to do ), if some one is SO cheap they cant or wont have the tank looked at and maybe save a life welllll...........im the only air fill in 100 miles ill fill a 6351 if its had a vaild eddy ...again if I trust the person /company who did it , REMEMBER ITS MY LIFE IM RISKING FOR 10 BUCKS !!! go to tobermory and spot the crap you just did and try to fill your tanks see what happens , those guys WONT fill anything over 10 years old .........
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Isn't Tobermory a location and should be capitalized as Tobermory ?

Do you and other Canadians accept 'Hawaiian Hydro's ?'

sdm

 

[Bob DBF]

Do you do this because you seriously think that people print their own stickers? What a bunch of baloney.

Although I have read, on ScubaBoard, where someone has printed their own VIP stickers, however the usual is to purchase from sites like the one below.

Visual Inspection Certificate Inspection Sticker

I don't know how many do that, but for a while, my old LDS used those stickers as well.


Bob

 

[Sam Miller III]

It was a chap called "Nimrod" from the dive capital of the world Kansas .

I suspect he is slowly exiting the diving world -- no post for over a year .

SAM

 

[Wookie]

Do you and other Canadians accept 'Hawaiian Hydro's ?'

sdm

Doc, what is a Hawaiian Hydro? I been doing this a long time and was certified out that way (go to Hawaii and them go another 800 or so miles to the middle of nowhere and stop) and this is the first time I've heard the term.

 

[Nettie-NZ]

I'm not questioning your credentials. I'm sure you can UT with the best of them, and write procedures that could astound the smartest guys.

But we're not talking carbon cylinders here, we're talking about a specific test to find a specific problem in a cylinder made from a specific alloy. The cracking is in alloy 6351-T6 aluminum. If the test is performed on a different cylinder, the results are meaningless.

If I used your carbon cylinder inspection techniques to inspect a fiberglass cylinder, would you accept the results? More to the point, would the results mean anything?

C'mon, you work in QA. You know better than to use a test for one material on another.

As a professional engineer I have written specifications requiring NDT inspections on a variety of industrial equipment including large pressure vessels and tanks and large rotating equipment (hydro turbines and generators).

Eddy current inspections are a routine test with meaningful results in a number of industries. It is particularly useful for detecting subsurface flaws. I’ve seen it used extensively for inspections for subsurface cracking in large paper machine roll bearing stub shafts as well as other thread cracking situations where it is very costly to disassemble components to inspect a thread directly.

Yes, a specific test procedure is required, and that procedure may be different to the one used for detecting thread cracking in 6351 Al alloy cylinders. However it still gives very meaningful and accurate results to a NDT technician who is trained and qualified to interpret them.

NDT (or NDE depending on where in the world you are from) is an ever expanding field - here’s a link to a page that might help you broaden your understanding of Eddy Current testing
Introduction to Eddy Current Testing | Olympus IMS

 

[nadwidny]

It was a chap called "Nimrod" from the dive capital of the world Kansas .

I suspect he is slowly exiting the diving world -- no post for over a year .

SAM

I believe he was banned from S'Board a few months ago. Over what I have no idea.

 

[Wookie]

As a professional engineer I have written specifications requiring NDT inspections on a variety of industrial equipment including large pressure vessels and tanks and large rotating equipment (hydro turbines and generators).

Eddy current inspections are a routine test with meaningful results in a number of industries. It is particularly useful for detecting subsurface flaws. I’ve seen it used extensively for inspections for subsurface cracking in large paper machine roll bearing stub shafts as well as other thread cracking situations where it is very costly to disassemble components to inspect a thread directly.

Yes, a specific test procedure is required, and that procedure may be different to the one used for detecting thread cracking in 6351 Al alloy cylinders. However it still gives very meaningful and accurate results to a NDT technician who is trained and qualified to interpret them.

NDT (or NDE depending on where in the world you are from) is an ever expanding field - here’s a link to a page that might help you broaden your understanding of Eddy Current testing
Introduction to Eddy Current Testing | Olympus IMS

Thanks for that. I perform underwater Ultrasonic Testing of ships hulls for a good time. Although I am not a metallurgist, and am merely a lowly technician, I understand the importance of procedures as it comes to performing NDT, and the problems you can run into when using the wrong procedures or tools to test the wrong materials.

What I am is a nuclear engineering technologist (4 year degree). I am fairly sure that different materials are subject to different failure modes when subject to different stresses, such as neutron flux or heat. Austenitic Stainless Steel is subject to chloride stress corrosion, where inconel is subject to chloride pitting corrosion. Hint. The failure modes are different, and the methods for testing are also different.

The Visual Plus machine is perfectly capable of detecting sustained load cracking defects in 6351 cylinders. As 6061 cylinders are not subject to sustained load cracking, the test is worthless unless a manufacturing defect is present in the cylinder, one that was missed by the manufacturer.

But thanks for man'splaining NDE to me.

 

[Nettie-NZ]

I’m not trying to flame you, just putting some facts on the table about the range of applications possible with eddy current testing.

Aluminium alloys aren’t my area of expertise so I’m not going to comment on 6351 vs 6061. But I have had a fair bit to do with stainless steels including austentic and some plain carbon steels.

Failure modes aren’t black & white - it’s more of a continuum with a variety of variables - It’s not that a specific austentic stainless eg 316L vs 304L isn’t susceptible to chloride pitting corrosion, it that it is one is a little less susceptible and the other one slightly more.... ....and by a range of environments I’m not limiting this to solely marine applications.

As for the man’splaining comment - that just shows that sexism is still thriving.

‘Nuf said - I’d rather be diving anyway

 

[Wookie]

Arguing with an engineer is like fighting a pig in mud - After the first few hours, you realise they enjoy it.